A principal aim of the study is to discover the nature of the relationship between societal development and the propensity for forming, joining, and participating in representative associations. The author describes how interest groups have affected and been affected by industrialization, bureaucratization, urbanization, social mobilization, and increase in the equality of conditions. He also shows how these groups, by exhibiting on a smaller scale the conflict between such values as traditionalism and modernism, religiosity and secularism, corporatism and liberalism, reflect and support the Brazilian political culture as a whole. Finally, he examines the way Brazilian associations have influenced political decision-making during a time of fluctuating policy toward freedom of association